Paint not showing up in Cycles?
This is an anser to your second question.

Yes, you can have textures and materials at the same time. In fact, you can't have textures without materials.

In cycles, you add an image texture node (found in texture, image), and then you select the path to your image, and simply connect that into the color input of the shader you want to color (or node that you want to input a texture to)